The invention relates to subsea well intervention.
Subsea wells are typically completed in generally the same manner as conventional land wells and are subject to similar service requirements as land wells. Further, as with land wells, services performed by intervention can often increase the production from the subsea well. However, intervention into a subsea well to perform the desired services is typically more difficult than for land wells. Conventionally, to perform subsea intervention, the operator must deploy a rig (such as a semi-submersible rig) or a vessel, as well as a marine riser, which is a large tubing that extends from the rig or vessel to the subsea wellhead equipment.
Interventions may be performed for various reasons. For example, an operator may observe a drop in production or some other problem in the well. In response, the operator performs an intervention operation, which may involve running a monitoring tool into the subsea well to identify the problem. Depending on the type of problem encountered, the intervention can further include shutting in one or more zones, pumping a well treatment into a well, lowering tools to actuate downhole devices (e.g., valves), and so forth.
Although intelligent completions may facilitate the determination of whether to perform intervention, they do not offer a complete range of desired intervention solutions. In addition, not all wells are equipped with the technology.
Performing intervention operations with large vessels and heavy equipment such as marine riser equipment, as conventionally done, is typically time consuming, labor intensive, and expensive. Therefore, a need continues to exist for less costly and more convenient intervention solutions for subsea wells.
In general, according to one embodiment, an apparatus for use with a subsea well comprises subsea wellhead equipment and a carrier line spool having a carrier line and that is positioned underwater. An underwater marine unit is adapted to attach the carrier line to the subsea wellhead equipment.
Other features and embodiments will become apparent from the following description, from the drawings, and from the claims.